Elderly individuals often suffer from sleep disturbances, such as frequent nocturnal awakenings or early morning arousal, as indicated by verbal complaints of not having slept well (Foley et al., 1995). The consequences of chronic sleep problems can be considerable with significant medical, psychological, and social disruptions (Vgontzas & Kales, 1999). Although there is much research about sleep, few studies have focused on methods for improving quality of sleep. Thus, there is a need to develop interventions comprising non-pharmacological, behavioral modification techniques to promote quality of sleep and improve health status. This proposed study is designed to examine the effects of a Tai Chi program, incorporating meditation and breathing with whole body movements, on improving the quality of sleep among sedentary elderly individuals. Using a randomized experimental design, potential participants, to be identified through the Pittsburgh Sleep Quality Index questionnaire (PSQI), will be randomly assigned to a Tai Chi group or an exercise control group. Each group will have 50 subjects exercising 3 times per week for 60 minutes. The length of the study will be set at nine months, with outcome measures related to the quality of sleep and health status taken at baseline, 3 months and 6-month, termination of the study, and 3-month follow-up. The primary aims of this study are to: (a) determine the effects of Tai Chi practice, in comparison to a conventional exercise control group, on the quality of sleep among older adults, and (b) examine the relationships between change in quality of sleep and change in health-related quality of life indicators as a result of Tai Chi exercise. The secondary aims of the study are to: (a) compare the effectiveness of the 2 activity conditions (Tai Chi and conventional exercise activity) on quality of sleep and health related quality of life, (b) explore psychological variables that could potentially serve as moderators of the activity - sleep quality relationship, and (c) examine long-term effects of activity on quality of sleep and well-being.